<?php
declare (strict_types = 1);

namespace app\model;

use think\Model;

/**
 * @mixin \think\Model
 */
class A extends Model
{
    function b(){
//        return $this->hasOne(B::class,'id','b_id');
        return $this->belongsTo(B::class,'b_id','id');
    }
    function c(){
        return $this->belongsTo(C::class,'c_id','id');
    }
}
